The present invention relates to improvements in exhaust gas recirculation manifolds for internal combustion engines, although some applications may be outside of this field.
Since the mid 1970s, it has been appreciated that the recirculation of exhaust gas into the inducted air of the intake manifold produces certain benefits in terms of reduced emissions. Typically, a small amount of exhaust gas is taken from the exhaust manifold, passed in appropriate plumbing to a controlling component such as a valve, and then introduced through a fitting into the intake manifold. Various designs relate to this area, including:
______________________________________ Patent No. Patentee Issue Date ______________________________________ 5,490,488 Aversa et al. 2/13/96 4,870,941 Hisatomi 10/3/89 4,072,133 McWhirter 2/7/78 5,490,488 Aversa et al. 2/13/96 3,717,130 Thornburgh 2/20/73 3,717,131 Chana et al. 2/20/73 5,492,104 Elder et al. 2/20/96 5,609,144 Seizew et al. 3/11/97 3,892,026 Thornburgh 7/1/75 5,425,347 Zinke, II 6/20/95 5,542,711 Vaudry 8/6/96 5,329,912 Matsumoto et al. 7/19/94 4,609,009 Tisone 9/2/86 2,034,144 Lauret 3/17/86 5,427,080 Maeda et al. 6/27/95 4,276,865 Hamai 7/7/81 5,474,102 Lopez 12/12/95 ______________________________________
Many of these designs tend to produce less than adequate distribution of recirculated exhaust gas among multiple cylinders, especially when there is a single entry point for the recirculated exhaust gas, or when the recirculated exhaust gas is cooled or introduced in large flow rates. Cooling of the exhaust gas results in another problem of condensation of an acidic and corrosive mixture.
What is needed is an improved exhaust gas recirculation (EGR) manifold, which the present invention proposes in a novel and unobvious way.